Securing members together by spring rings

ABSTRACT

A spring ring ( 41 ) of rectangular cross section has adjacent its ends arms which extend generally radially outwardly. The ring ( 41 ) is used to hold together two members ( 31, 40 ) in telescopic engagement by engaging in an internal groove ( 45 ) in one member and in an external groove ( 46 ) in the other. During assembly of the members the ring is located entirely in one of the grooves by a holding element ( 51 ) supported wholly by the arms on the ring. After assembly the holding element is withdrawn radially outwardly through a slot ( 47 ) in the external member.

TECHNICAL FIELD

This invention relates generally to the securing together againstrelative axial movement of two members in telescopic relation. Themembers are secured together by a spring ring which is received incooperating grooves, an internal groove in the external member and anexternal groove in the internal member.

BACKGROUND ART

It is known to have internal and external members as above described inwhich a spring ring of circular cross section is mounted, for example,in the internal groove of the external member and the free end of theinternal member is provided with a chamfer. As the free end is pushedinto the external member the chamfer expands the ring and allows theinternal member to telescope into the external member until the externalgroove in the internal member is aligned with the internal groove in theexternal member whereupon the ring contracts and engages the side wallsof both grooves to hold the members against relative axial movement.

In this arrangement the relative dimensions of the grooves and the ringare critical since when the ring is open it must pass over the internalmember but when it contracts and is in its closed state it must engagethe walls of both of the aligned grooves to hold the members againstrelative axial movement.

In some applications where greater security is required than is given bya ring of circular cross section, a ring of rectangular section is used,the section normally having a greater dimension radially than axially.When using such a ring it tends to fall to the bottom of the internalgroove in the external member and a chamfer on the internal member willnot lift the ring nor open the ring when the members are telescopedtogether. Normally, therefore, such rings have apertured ears at oradjacent their ends and are opened by normal circlip pliers to allowassembly of the members. After assembly the ears are released when thegrooves are aligned. In such an arrangement the external groove willhave a slot in its base through which the ears will project so as to beaccessible to the circlip pliers. In this construction it is againnecessary that there is a very specific relation between the dimensionsof the ring and of the grooves. The internal groove in the externalmember must be deep enough to receive the ring completely to allowassembly and the external groove will be less deep.

While in the foregoing we have described the spring ring being held openduring assembly of the members, it is equally possible for the springring to be held closed during assembly of the members and then releasedso that it expands into mutually aligned grooves in the members to holdthem together. In such a case the external groove in the internal membermust be deep enough to receive the ring completely to allow assembly andthe internal groove will be less deep.

It has previously been proposed in GB-A- 1 514 690 to have a bridgemember which fits into the holes in the ends of a normal circlip andwhich may be used to hold the circlip open or closed during an assemblyoperation and then removed to allow the circlip to spring back to itsunstressed state. In this arrangement the bridge piece has to be removedin a direction perpendicular to the plane of the circlip and in manyassemblies this is not possible.

GB-A-349 329 shows, in FIG. 1, a ring to hold a gudgeon pin in place byengaging in an internal groove in the pin bore. The ring is held in itsexpanded state by a grooved disc inserted between internally projectingarms on the ring. This arrangement is not suitable for manyapplications.

Finally, in GB-A-1 137 436 there is shown an arrangement in which anexternal member has an internal groove which opens through a slot to theexterior of the member and a circlip is used which has long arms whichproject through the slot into a recess. The circlip can be held bycirclip pliers in a closed position during assembly of the members andthen allowed to expand to hold the members together. In this case thereis no external groove in the internal member. This arrangement is notsuitable for use in many applications where there is no access to beable to engage the arms of the circlip with circlip pliers.

In GB-A-1 223 050 there is disclosed an assembly of an external memberin telescopic relation with an internal member, the external memberhaving a bore, an internal groove in the bore and a slot extendingradially of the bore between an inner end open to the bore and an outerend at the external surface of the external member, the slot extendingaxially between said groove and an end of the external member. Theinternal member and the external member are capable of being held inassembled position by a spring ring engaged in said groove and in anexternal groove of the internal member, the ring having, adjacent itsends, arms which extend generally radially outwardly into said slot. Toassemble the members the end portions of the arms, which extend radiallyoutwardly of the slot, have to be drawn together while the parts aretelescoped and then released. To enable said end portions to be drawntogether it is necessary to have access to the external member duringthe telescoping operation. In some circumstances, eg. where the externalmember is itself surrounded by another element, this is not possible andthis prior construction is not usable.

In US-A-3 701 303 there is shown, in FIGS. 5 and 6, a stop ring forfitting onto a shaft having a groove. The stop ring has arms on whichthere are formations which may be engaged by the nipples of pincers forexpanding the ring. The pincer nipples may be engaged with anddisengaged from the arm formations in directions radially of the ring.Again this arrangement requires radial access to the ring which is notalways possible.

Thus in many applications using rings of rectangular section it is notconvenient or even possible to use circlip pliers to hold the ring openor closed during assembly of internal and external members eitherbecause of the location of the grooves with reference to other parts ofan assembly and/or the method of assembly of the members. In thesecircumstances, none of the known arrangements described above would besuitable for assisting in the assembly of the members.

In such circumstances, therefore, it is necessary to find some means ofholding the spring ring open or closed while assembling the members intelescopic relation and then allowing the ring to be released tocontract or expand to its normal form when the internal and externalgrooves are aligned so that the ring engages the walls of both groovesto hold the members in the desired axial position.

DISCLOSURE OF INVENTION

It is an object of one aspect of the invention to provide a method ofsecuring together, by means of a spring ring, two members in telescopicrelation which may be used in confined situations where the prior art isnot usable.

According to this aspect of the invention we provide a method ofsecuring together, by means of a spring ring, an external member intelescopic relation with an internal member, wherein the external memberhas a bore, an internal groove in the bore and a slot extending radiallyof the bore between an inner end open to the bore and an outer end atthe external surface of the member, the slot extending axially betweensaid groove and an end of the member, and wherein the spring ring isengaged in said groove to locate the internal member and has, adjacentto its ends, arms which extend generally radially outwardly into saidslot; characterised in that the internal member has an external grooveand in that the method comprises mounting the spring ring in one of saidgrooves, releasably holding the ring in a contracted or expanded stateso that it lies substantially within said one groove by engaging thering arms with a holding element which is supported wholly by the ring,telescoping the members together while the arms are engaged with theholding element until the grooves in the members are mutually alignedand so that the ring arms and holding element are located in said slotand withdrawing the holding element radially through the outer open endof the slot thus disengaging said arms from the holding element andreleasing the ring so that the ring expands or contracts to engage inboth of the mutually aligned grooves to secure the members together.

It is an object of another aspect of the invention to provide atelescopic assembly capable of being secured together by the method setforth above.

According to this aspect of the invention we provide a telescopicassembly of an external member and an internal member, wherein theexternal member has a bore, an internal groove in the bore and a slotextending radially of the bore between an inner end open to the bore andan outer end at the external surface of the member, the slot extendingaxially between said groove and an end of the member, the members beingheld in assembled position by a spring ring engaged in said groove andlocating the internal member, the ring having, adjacent its ends, armswhich extend generally radially outwardly into said slot; characterisedin that the internal member has an external groove and the ring engagesboth of said grooves to hold said members assembled.

It is an object of another aspect of the invention to provide thecombination of a spring ring and a holding element which is usable inthe method and assembly referred to above.

According to this aspect of the invention we provide the combination ofa spring ring of rectangular cross section, the ring having a state ofrest in which it is in either an open state or a closed state and hasends adjacent to which are arms which extend generally radiallyoutwardly, with a holding element dimensioned to engage said armsreleasably to hold the ring out of its state of rest in a stressed statein which the ring is in either a closed state or open staterespectively; characterised in that (1) the holding element hasoppositely-facing surfaces which engage generally-radial,oppositely-facing surfaces on the edges of the arms to hold the ring inits stressed state, (2) in that said surfaces on the arms and theholding element can be disengaged by radially outward movement of theholding element relative to the arms and (3) in that the holding elementhas a part remote from said surfaces whereby it may be gripped.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail by way of example withreference to the accompanying drawings in which:

FIG. 1 is a cross section through an assembly of a motor vehicle wheelbearing and a constant velocity joint in which the two members areconnected together by the method according to the invention;

FIG. 2 is an elevation of the spring ring used in the assembly of FIG.1;

FIG. 3 is a perspective view of a holding element with its internalshape shown dotted and which is used in the assembly of the membersshown in FIG. 1;

FIG. 4 is a cut-away perspective view of part of the assembly shown inFIG. 1;

FIG. 5 is an enlarged view of part of FIG. 4 illustrating the holdingelement and both ends of the spring ring;

FIG. 6 is a detail cross-section showing the spring ring in position inthe assembly;

FIG. 7 is an elevation of a modified form of spring ring with a holdingelement holding the ring closed;

FIG. 8 is a detail of FIG. 7 but showing the holding element holding thering open;

FIGS. 9 and 10 are detail views of alternative formations of the arms onthe ring of FIG. 7;

FIG. 11 is a perspective view of the holding element shown in FIG. 7 and8;

FIG. 12 is a plan view of the holding element of FIG. 11;

FIG. 13 is a plan view of a slightly different form of holding element;

FIG. 14 is an elevation of a further modified form of spring ring usablein the invention;

FIG. 15 is an elevation of the ring of FIG. 14 showing a tool to bringits ends together;

FIG. 16 is a detail view showing a holding element embracing the arms onthe ring; and

FIG. 17 is a detail view of a modified holding element holding the armsof the ring apart.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring first to FIG. 1, the steering knuckle of a motor vehicle isindicated at 20 and has means 21 and 22 at its upper and lower ends forconnection to the suspension of the motor vehicle. The knuckle isprovided with a central aperture 23 in which is mounted a wheel bearingindicated generally at 24. The inner part of the wheel bearing isindicated at 25 and has a flange 26 to which a brake disc 27 can beattached by bolts, not shown. The outer part of the wheel bearing isindicated at 28 and is secured to the knuckle by bolts, one of which isindicated at 29. Between the inner and outer bearing parts are two rowsof bearing balls 30, the inner race of the right hand row being providedby a ring 31 which is held in position by a further ring 32 which inturn is held in position by the swaged inner end 33 of the inner part 25of the wheel bearing. The outer surface of the ring 32 is splined asindicated at 34.

A constant velocity joint is indicated generally at 35 and comprises anouter race 36, an inner race 37, balls 38 received in grooves in theinner and outer races and a cage 39. Secured to the outer race is aninternally splined ring 40 which fits on the splines 34 of the ring 32.The rings 32 and 40 are held together by a spring ring 41 received in aninternal groove in the ring 40 and an external groove in the ring 32 aswill be described in more detail below. A drive shaft, not shown may beengaged in a splined bore 37 a in the inner race 37.

FIG. 2 shows the ring 41. The ring is of rectangular cross section andits radial dimension is greater than its axial dimension. The ring isprovided with two arms 42 at its ends. The outer surfaces of the arms 44diverge at a small angle of about 10-11°.

Referring to FIGS. 4, 5 and 6, the ring 41 is received in an externalgroove 45 in the ring 32 on the wheel bearing and an internal groove 46in the ring 40 forming part of the outer race of the constant velocityjoint. The spring ring is one which has a state of rest as shown in FIG.2 with the arms spaced from one another and may be contracted into astressed state in which the arms 42 approach one another. As shown inFIG. 6 the ring 41 substantially fills the internal groove 46 andprojects into the external groove 45.

It will be seen that the ring 40 is provided with a slot 47. This slotextends between the bore 48 of the ring 40 and its outer end 49 is atthe external surface of the ring. The slot also extends inwardly and hasan inner wall 50, the outer end of the slot being open to the outer endof the ring 40.

During assembly of the members, the ring is held in a contracted stateby means of a holding element 51 shown in detail in FIG. 3. The holdingelement may, for example, be moulded from plastic material or could bemade of metal. The holding element is made of a solid block and has acentral aperture 52. This aperture has a width w which is just greaterthan that of the arms 44 of the ring so that the arms can be engaged inthe aperture; the mouth of the aperture is chamferred at 53. The holdingelement has a portion 54 whereby it can be gripped. This portion isnarrower than the portion having the aperture 52.

To assemble the members the ring 41 is mounted in the groove 45 in thering 32 forming part of the inner part of the wheel bearing. The arms 42of the ring are then contracted together. The arms of the contractedring are inserted into the aperture 52 in the holding element 51 andthis holds the ring in its stressed position in which it is completelycontained within the internal groove 45 in the ring 32. During insertionof the arms 42 into the holding element the outer surfaces 44 of thearms 42 engage the chamfers 53 in the holding element.

The members are then telescoped together with the splines in the rings32 and 40 engaging one another and in an orientation such that, as theparts move together, the holding element 51 which is holding the arms ofthe ring 41, is received in the slot 47. When the parts are fullytelescoped, the internal groove 46 in the ring 40 will be aligned withthe internal groove in the ring 32 and the holding element 51 will belodged in the slot 47. The gripping portion 54 of the holding element isthen gripped and pulled radially outwardly of the slot thus releasingthe arms 42 on the ring 41 as shown in FIG. 5 and allowing the ring toexpand to its position shown in FIGS. 2 and 6. In this position the ringfully fills the external groove 46 and partially fills the internalgroove 45.

The holding element 51 is dimensioned to fit snugly in the slot 47 andcan be removed through a hole, not shown, in the knuckle 20. The holemay be that designed to receive the ABS sensor or may be providedspecially for the purpose. In FIGS. 4 and 5 the ABS ring is shown at 55.

It will be seen that the use of the holding element 51 enables the partsto be assembled together easily while the arms 42 of the ring are heldtogether by the element 51. It would not be possible to hold the armstogether with a pair of circlip pliers for example because the wheelbearing and CV joint are mounted in the knuckle and the ends of the ringare therefore not accessible except through a hole provided either forthe ABS sensor or for the holding element as mentioned above.

When the parts are assembled the ring is in its unstressed state asshown in FIG. 2. If desired a gauge may be inserted into the slot 47 toensure that the ring has fully expanded, the gauge being dimensioned toenter between the ring arms 42.

Alternatively, as will be described below, an appropriate part of theholding element may be provided which, if the element is inverted, willgo back into the slot and hold the ends of the ring open.

Referring to FIG. 7, a spring ring 60 is shown having a rectangularcross section in which the radial dimension is greater than the axialdimension. At its ends, the ring is provided with arms 61 which areshown in detail in FIG. 9. Each arm has an inwardly facing radialsurface 62 which is provided with a part-circular depression 63. Theoutwardly facing radial surfaces of the arms have inclined portions 64which terminate in projections 65. The outer radial surface of the ringis relieved at 61 a adjacent to each arm 61.

The holding element is indicated generally at 66 in FIG. 7 and is shownin more detail in FIGS. 11 and 12. The holding element may convenientlybe a plastic moulding. As is clear from FIGS. 11 and 12 the holdingelement is of generally U-shape having a base 67 and arms 68. A tab 69extends from the base and may be gripped with pliers to move the holdingelement into and out of position. The outer surfaces 70 of the arms 68have projections 71 and the inner surfaces 72 of the arms havedepressions 73. The outer walls 70 taper slightly to the ends 74.

As shown in FIG. 7, the holding element can be used to hold the ring inits closed position which may be its unstressed position. This iseffected by sliding the holding element into engagement with the arms 61in the direction of the arrow C in FIG. 7. The inclined portions 64 ofthe arms engage the surfaces 72 and as the holding element is movedinwardly in the direction of the arrow C the inner surfaces 72 move downthe inclined surfaces 64 until the projections 65 at the arms arereceived in the depressions 73 in the holding element. The holdingelement is thus held releasably in position and can be removed from thering by grasping the tab 69 and moving the holding element in thedirection opposite to the arrow C.

FIG. 8 shows how the holding element can be used to hold the ring in itsexpanded position e.g. in its stressed state. In this position theprojections 71 on the arms of the holding element are received in thedepressions 63 in the internal surfaces of the arms 61 and thus hold thering in its expanded position to allow assembly of two telescopicmembers.

The ring 60 and the holding element 66 may be used in assembling themembers described in relation to FIGS. 1, 4 and 5. Thus the ring may beinserted in the internal groove 46 in the ring 40 forming part of theouter race of the constant velocity joint with the arms 61 received inthe slot 47. The holding element 66 may then be inserted between thearms as shown in FIG. 8 to hold the ring in an expanded, stressedcondition so that it is wholly within the internal groove 46. The partsmay then be telescoped as described above until the grooves 45 and 46are in alignment whereupon the holding element 66 can be withdrawnthrough the slot 47 which will result in the ring returning to itsunstressed state as shown in FIG. 7 in which it will engage both grooves45 and 46.

The holding element can then be re-inserted into the slot 47 so that itassumes the position shown in FIG. 7 and holds the ring in itsunstressed state in engagement with both grooves. This prevents thepossibility of the ring expanding under centrifugal force in use todisengage itself from the groove 45.

During an assembly operation, therefore, once the ring 60 has beeninstalled and the holding element 66 replaced as shown in FIG. 7,inspection of the assembly will show that the ring is properlyinstalled.

FIG. 10 shows a somewhat different design of arm for a spring ring 85;it operates in a way similar to the arms shown in FIG. 9 but has roundedprojections 86 on the outer surfaces of the arms and recesses 87 on theinner surfaces thereof.

FIG. 13 shows a holding element 88 which is substantially identical tothat described in relation to FIGS. 11 and 12 except that instead ofbeing U-shaped in section it is in the form of a substantiallyrectangular tube with a wall 89 closing the mouth of the U. Theoperation of the holding element will be exactly as described above butthe extra wall prevents the holding element being inadvertently movedoff the arms in an axial direction.

A further modification of the invention will now be described inrelation to FIGS. 14 to 16. Referring now to FIG. 14, a spring ring isshown at 80. The ring has a rectangular section with the radialdimension of the transverse section of the ring being greater than theaxial dimension. The ends of the ring are indicated at 81 and in theunstressed state of the ring there is a gap 82 between the ends. Theends have radially outwardly-extending arms 83 and these have concaveformations 84 in their outwardly-facing surfaces. Formed in the outerperiphery of the ring adjacent to the arms are notches 85.

In using this ring to hold two telescopic members together, as describedabove in relation to FIGS. 4 and 5, the ring is mounted in the externalgroove 45 in the inner ring 32 and the ends 81 are then brought togetherby a tool as will be described. A holding element then engages the endsof the arms to hold the ring in its contracted state. When the partshave been assembled the holding element is removed and the ring returnsto its unstressed state shown in FIG. 14 as previously described.

FIG. 15 shows the notches 85 in the ring 80 being engaged by the ends ofjaws 86 of a plier-like tool T consisting of two arms 87 pivoted at 88.The arms 87 have handles 89. By moving the handles 89 towards oneanother the jaws 86 are brought towards one another and therefore theends 81 of the ring 80 are brought together.

When this has been done a holding element 90 can be slipped over thearms 83 to hold the arms 83 and the ends 81 together as shown in FIG.16. The holding element 90 is generally U-shaped having a base 91 andarms 92. The arms slope inwardly and have convex formations 93 whichengage in the concave formations 84 in the arms. The holding element 90may be made of resilient material so that it can be easily slid over theends of the arms 83 so that the convex formations 93 are received in theconcave formations 84.

The ring is used to hold together two telescopic members of the form,for example, as shown in FIGS. 4 and 5. In use, the ring 80 is placed inthe groove 45 in the ring 32 and if necessary is sprung open to bereceived in the groove. When the ring is in the groove, the notches 85are engaged by the jaws 86 of the tool T and the ends of the ring arebrought together. The holding member 90 is then slipped over the ends ofthe ring to hold it in a contracted position. In this position the ringis wholly received in the slot 45. As described above the parts aremoved so that the grooves 45 and 46 are in alignment and then theholding element 90 is removed through the slot 47 from the arms 83 whichallows the ring 80 to move to its unstressed state in which it fills thegroove 46 while also being partly received in the groove 45. Tofacilitate removal of the holding element the latter may have anaperture 92 formed in the base thereof which may be engaged with a hookor similar tool.

FIG. 17 shows a modified holding element. In this figure the holdingelement comprises a U-shaped part 93 having arms 94 which can engage thearms 83 on the ring 80 in a manner similar to that shown in FIG. 3 andalso a projecting portion 95 which, as shown, can be inserted into thegap 82 between the arms 83 when the ring is in its unstressed state. Theprojecting portion 95 may have projections 96 at its ends which arereceived in notches in the inwardly-facing surfaces 97 of the arms thusto retain the holding element in the position shown in FIG. 17.

In using the modified holding element, the insertion of the ring intothe groove 45 in the ring 40 and the assembly of the members would be asbefore. Once the holding element had been removed and the ring had movedto its unstressed state to engage in both grooves 45 and 46, the holdingelement would be turned round and the projection 95 inserted through theslot 47 into the gap 82 to hold the ring in its unstressed state thussubstantially filling the groove 46. The holding element would bereleasably held in position by the projections 96 as described.

It will be seen that the invention provides a means and method forassembling two members to be held together with a spring ring incircumstances when access to the ring by normal circlip pliers isprecluded.

What is claimed is:
 1. A method of securing together, by way of a springring of rectangular cross-section, an external member in the form of anouter race of a constant velocity joint in telescopic relation with aninternal member in the form of part of a motor vehicle wheel bearing,wherein the external member comprises a bore, an internal groove in thebore and a slot extending radially of the bore between an inner end opento the bore and an outer end at an external surface of the member, theslot extending axially between said groove and an end of the member,wherein the internal member has an external groove, wherein the springring is engaged in said grooves to secure the members together and has,adjacent to its ends, arms which extend generally radially outwardlyinto said slot, the method comprising: mounting the spring ring in thegroove in the internal member; releasably holding the ring in acontracted state so that it lies substantially within said groove;telescoping the members together while the ring is in said contractedstate until the grooves in the members are mutually aligned and so thatsaid arms move along the slot from said end of the external member; andreleasing the ring so that the ring expands to engage in both of themutually aligned grooves to secure the members together, and whereingenerally radial, oppositely-facing surfaces on the arms are engagedwith oppositely facing surfaces on a holding element prior to thetelescoping of the members so as to hold the ring in said contractedstate in the groove of the internal member, the holding element beingsupported solely by the arms, the holding element moving along the slotfrom said end of the external member as the members are telescoped andbeing located in said slot when the members have been telescoped so thatsaid grooves are aligned and the holding element being disengaged fromsaid arms to release the ring to expand to engage in both of saidgrooves by radial movement out of said slot.
 2. A method according toclaim 1 comprising, after the holding element has been disengaged fromsaid arms so that the ring has expanded to engage in both of saidgrooves, inserting the holding element into the slot and engaging theholding element with generally radial, oppositely; facing surfaces onthe arms by relative movement of the holding element and the arms in adirection radially of the ring so that the holding element is supportedsolely by the arms and holds the ring in its expanded state in which itis engaged in both of said grooves.
 3. A method according to claim 1comprising engaging the holding element with outwardly facing surfaceson the arms to hold the ring in said contracted state.
 4. A methodaccording to claim 1 wherein the ring, when the members are securedtogether, lies within an aperture in a vehicle steering knuckle securedto the internal member, said knuckle having a radial hole opening intosaid aperture and in line with the groove in said internal member; andwherein the holding element moves into the aperture of said knuckle asthe members are telescoped together, the holding element beingdisengaged from the arms by gripping a portion of the holding elementthrough said radial hole and withdrawing the holding element radially ofthe ring through the outer open end of the slot and the radial hole. 5.A method according to claim 1 wherein the ring has formations in itsouter periphery adjacent to the arms for engagement by a tool and iscontracted by the tool engaging with said formations when the ring is inthe external groove of the internal member after which the arms areengaged by the holding element and the tool is disengaged from the ringso that the holding element is supported solely by the arms.
 6. Anassembly comprising: an external member in the form of the outer race ofa constant velocity joint and having a bore, an internal groove in thebore and a slot extending radially of the bore between an inner end opento the bore and an outer end at an external surface of the member; theslot extending axially between said groove and an end of the member, aninternal member in the form of part of a motor vehicle wheel bearing intelescopic relation with the external member, the internal member havingan external groove axially aligned with the internal groove; a springring of rectangular cross-section adapted to engage said aligned groovesto secure the members together, the ring comprising, adjacent to itsends, arms which extend generally radially outwardly into said slot; anda holding element located in said slot, wherein generally radial,oppositely-facing surfaces on the arms are engaged with oppositelyfacing surfaces on said holding element so as to hold the ring in acontracted or expanded state so that the ring lies either substantiallyin the groove of the internal member or in both of the grooves theholding element being supported solely by the arms within the slot. 7.An assembly according to claim 6 wherein the holding element comprises aU-shaped cross section, the surfaces of the arms of the U-shapeproviding said oppositely-facing surfaces which engage the arms to holdthe ring in its contracted state.
 8. An assembly according to claim 7wherein the holding element comprises a hollow rectangular shape incross-section and is dimensioned to receive the arms of the ring withinthe rectangle shape to hold the arms so that the ring is in itscontracted state.
 9. An assembly according to claim 7 wherein theholding element is engaged with outwardly facing surfaces on the arms tohold the ring in said contracted state.
 10. An assembly according toclaim 6, wherein in that the holding element has a part whereby it maybe gripped to remove it from the slot; said part being inserted betweenthe ring arms to hold the ring in both grooves.
 11. An assemblyaccording to claim 6, wherein the ring has formations in its outerperiphery adjacent to the arms for engagement by a tool to contract thering to its closed state so that the holding element can be engaged withsaid arms.
 12. A method of securing together, by means of a spring ring(41, 60, 80), an external member (36, 40) in telescopic relation with aninternal member (25, 32), wherein the external member has a bore (48),an internal groove (46) in the bore and a slot (47) extending radiallyof the bore between an inner end open to the bore and an outer end (49)at the external surface of the member, the slot extending axiallybetween said groove and an end of the member, wherein the internalmember (25, 32) has an external groove (45), wherein the spring ring isengaged in said grooves to secure the members together and has, adjacentto its ends, arms (42, 61, 83) which extend generally radially outwardlyinto said slot (47); the method comprising mounting the spring ring (41,60, 80) in one of said grooves (45, 46), releasably holding the ring ina contracted or expanded state so that it lies substantially within saidone groove, telescoping the members together while the ring is in saidstate until the grooves in the members are mutually aligned andreleasing the ring so that the ring expands or contracts to engage inboth of the mutually aligned grooves (45, 46) to secure the memberstogether; the method being characterised in that generally radial,oppositely-facing surfaces (44, 62, 63, 64, 65, 83, 84, 86, 87) on thearms are engaged with oppositely facing surfaces (53, 70, 72, 92, 93,94) on a holding element (51, 66, 88, 90) prior to the telescoping ofthe members so as to hold the ring in said contracted or expanded statein said one groove and so that the holding element is supported solelyby the arms, in that the holding element is located in said slot whenthe members have been telescoped so that said grooves are aligned, andin that the holding element is disengaged from said arms to release thering by radial movement out of said slot.